title: [Zinc-protein binding in different types of milk and the effect of pepsin (author's transl)].
abstract: Human milk, cow milk and an infant formula containing skimmed milk and demineralized whey with and without added ZnSO4 were separated by gel chromatography. The bulk of zinc from all four types of milk eluted with a high-molecular protein fraction. In human milk zinc in an additional peak which corresponded to a protein fraction with an approximate molecular weight of 10(4) Daltons. The zinc-binding ligands described in the literature are of comparable size. After incubation with pepsin at pH 2, all zinc was eluted from human milk with the low-molecular protein fraction (1-1.5 x 10(4) Daltons). Incubation of the infant formula also resulted in the appearance of a new zinc peak at 1-1.5 x 10(4) Daltons. These data show that zinc-protein binding is markedly affected by peptic digestion. It appears possible that low-molecular zinc-binding ligands are present in milk types other than human milk and that they are released from aggregated by peptic digestion.
mesh_terms: D000418:Albumins / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D005260:Female; D006801:Humans; D007223:Infant; D007225:Infant Food / Q000032:analysis*; D007231:Infant, Newborn; D008892:Milk / Q000378:metabolism*; D008895:Milk, Human / Q000187:drug effects / Q000378:metabolism; D010434:Pepsin A / Q000494:pharmacology*; D011247:Pregnancy; D011485:Protein Binding / Q000187:drug effects; D015032:Zinc / Q000378:metabolism*
chemical_list: D000418:Albumins; D010434:Pepsin A; D015032:Zinc
vernacular_title: Zinkbindung an Eiweiss in verschiedenen Milcharten und Einfluss von Pepsin.